NIH study finds exposure to flame-retardant chemicals during pregnancy was associated with varying childhood obesity risks

Exposure to organophosphate esters (OPEs)—chemicals found in everyday products that use plastics and flame retardants—during pregnancy may have varying effects on the risks of childhood obesity, according to a new study funded by the Environmental influences on Child Health Outcomes (ECHO) Program at the National Institutes of Health.

The study found that children aged 5 to 10 years who were exposed to higher levels of dibutyl phosphate and di-isobutyl phosphate (DBUP/DIBP) during pregnancy had a 14% greater risk of developing obesity compared to those with the lowest exposure levels. In contrast, children whose mothers had higher exposure levels of bis (1,3-dichloro-2-propyl) phosphate (BDCPP) during pregnancy had a 15% lower risk of developing obesity than those with the lowest levels of exposure.

“We are just beginning to understand how OPE exposure might be connected to obesity. Our findings suggest that the relationship between OPE exposure during pregnancy and childhood obesity is complicated, and more research is needed to look at a wider range of OPE chemicals,” said Assiamira Ferrara, MD, PhD, senior research scientist at Kaiser Permanente Northern California Division of Research.

These chemicals are OPEs, which replaced polybrominated diphenyl ethers (PBDE) as flame retardants and plastic softeners in the mid-2000s. Studies in toxicology and epidemiology suggest that these substances can interfere with hormone systems and may be linked to obesity.

The study involved 5,087 mother-child pairs from 14 ECHO Cohort Study Sites. Researchers measured the levels of OPEs in the mother's urine during pregnancy and their children's body mass index (BMI) during infancy up to age 10. The participants were pregnant between 2006 and 2020 when OPEs were being rolled out to replace PBDEs.

“These findings underscore the need for further research to inform public health programs and regulatory policies aimed at mitigating childhood obesity risks from environmental chemical exposures,” said Alicia K. Peterson, PhD staff scientist at Kaiser Permanente Northern California Division of Research.

Researchers across the ECHO Cohort reviewed and analyzed data for this study. This collaborative research was published in Environment International.

Peterson, AK, et al. “Gestational Exposure to Organophosphate Ester Flame Retardants and Risk of Childhood Obesity in the Environmental influences on Child Health Outcomes.” Environment International. DOI: 10.1016/j.envint.2024.109071.

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About ECHO: Launched in 2016, the Environmental influences on Child Health Outcomes (ECHO) Program is a research program in the Office of the Director at the NIH with the mission to enhance the health of children for generations to come. ECHO investigators study the effects of a broad range of early environmental influences on child health and development. For more information, visit echochildren.org.

About the NIH: NIH, the nation’s medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information, visit www.nih.gov.